The fabrication of de novo proteins able to self-assemble on the nano- to meso-length scales is critical in the development of protein-based biomaterials in nanotechnology and medicine. Here we report the design and characterization of a protein engineered coiled-coil that not only assembles into microfibers, but also can bind hydrophobic small molecules. Under ambient conditions, the protein forms fibers with nanoscale structure possessing large aspect ratios formed by bundles of α-helical homopentameric assemblies, which further assemble into mesoscale fibers in the presence of curcumin through aggregation. Surprisingly, these biosynthesized fibers are able to form in conditions of remarkably low concentrations. Unlike previously designed coiled-coil fibers, these engineered protein microfibers can bind the small molecule curcumin throughout the assembly, serving as a depot for encapsulation and delivery of other chemical agents within protein-based 3D microenvironments.

The formation factor (ratio of bulk resistivity of rock to resistivity of formation fluid) obtained from the focused‐electrode log can be used to estimate the hydraulic conductivity of the unfractured granitic rock matrix [Formula: see text], using an empirical relationship developed between laboratory measurements of formation factor and permeability. The ratio of the formation factor derived from the focused‐electrode log [Formula: see text] to the formation factor derived from the density log [Formula: see text] may be used to estimate the hydraulic conductivity of fractured zones [Formula: see text], because of the following empirical relationship between the transmissivity [Formula: see text] obtained from the in situ hydrogeologic tests and the ratio of the two formation factors, namely, [Formula: see text] where A and s are coefficients [Formula: see text]. This empirical relationship confirms the usefulness of geophysical logs for identifying intervals of potentially high permeability in boreholes drilled in granitic rock. Estimates of hydraulic conductivity derived using these relationships can help obtain a qualitative understanding of hydrological conditions in a crystalline rock mass.

We demonstrate the fabrication of protein·gold nanoparticle (AuNP) nanocomposites in situ, leading to distinct assemblies dependent upon protein secondary structure. In the presence of pentameric coiled-coil proteins C and Q, which contain histidine tags and have helicities of 54 and 65%, respectively, templation of AuNP results in precipitation of the protein·AuNP composites with AuNPs 6.5 nm in diameter, creating macromolecular assemblies on the micrometer scale. In the absence of the histidine tags, the resulting Cx and Qx proteins, which exhibit lower helicities of 37 and 45%, respectively, stabilize soluble protein·AuNP composites with AuNPs 4.5 nm in diameter for several days without aggregating. By manipulating protein structure via external triggers, such as TFE, we obtain control over the macromolecular conformation and overall physicochemical properties. These hybrid protein·AuNP assemblies can be readily deposited on electrodes, where they can serve as a tunable bionanocomposite kinetic barrier.

Abstract-Quantitative pyrolysis gas chromatography studies have been conducted on three grades of crosslinked polyester resin formulated for improved resistance to surface spread of flame. Pyrolysis temperatures from 723 to 1273 K were used, and these values correspond to 'surface' temperatures of materials exposed to heat fluxes of 15-149 k W m-2 which are typical of conditions experienced in real fires. Comparison is made with earlier macro studies on the evolution of smoke from plastics materials exposed to similar heat fluxes under an inert atmosphere. There is some correlation between the smoke obscuration data obtained in previous macro studies and the yield of volatile aromatic products evolved on pyrolysis. The presence of flame retardants increases the formation of carbon in the pyrolysis residue and decreases the yield of volatile aromatic products isolated. The results are considered in the context of mechanisms of smoke formation.